ARM: OMAP4: hwmod: flag hwmods/modules not supporting module level context status

On OMAP4 most modules/hwmods support module level context status. On
OMAP3 and earlier, we relied on the power domain level context status.
Identify all modules that don't support 'context_offs' by adding a
flag bit, HWMOD_OMAP4_NO_CONTEXT_LOSS_BIT.  Rest have a valid
'context_offs' populated in .prcm structure already.

Signed-off-by: Tero Kristo <t-kristo@ti.com>
[paul@pwsan.com: add flag bit rather than overloading .context_offs;
 update changelog message]
Signed-off-by: Paul Walmsley <paul@pwsan.com>